Despite significant progress obtained in the last two decades, the performance of GaN electronic devices is far from the limits of this material, which we believe is due to the challenges in material growth.
Therefore, it is crucial to understand the fundamental issues from the perspective of epitaxial growth and then to explore a new approach toward these theoretical limits.
In this study, we have explored an approach toward the limit of GaN materials by means of using our high-temperature AlN buffer, which was originally designed for the growth of novel III-nitride optoelectronics (18−22) instead of the classic two-step growth method, where a 2D growth mode is employed throughout the whole growth process. A record breakdown field of 2.5 MV/cm has been demonstrated.
Furthermore, high-voltage AlGaN/GaN HEMTs with an extremely low off-state buffer leakage current of down to 1 nA/mm at up to 1000 V have been obtained.
The presented results also imply that it is possible to achieve the intrinsic limits of GaN electronics by further exploring epitaxial growth on large lattice-mismatched and industry compatible substrates.
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